Deprecated-but-readable table fields?

[maxburke]

I'm wondering if there's a way to have fields that are deprecated for writing, but still have read accessors available. We have a bunch of serialized objects where we would like to soft-migrate to the non-deprecated attributes, but would still like to read the old values if they exist.

[dbaileychess]

Not off the top of my head. We could add an attribute to only deprecate the writing part.

[dbaileychess]

I would take a PR for this if you are interested, not high enough on my list to do myself.

[maxburke]

@dbaileychess Understandable, let me see if I can fit it in.

What would you think of the name readonly for the attribute?

[dbaileychess]

I think I would prefer deprecated_writes or something, to indicate that the field is in progress to be deprecated.

Or deprecated_readonly would work.

[stephanemagnenat]

I would also have the use for that feature!

[Zguy]

Yes! Every time I reach for the deprecated attribute, I find that something like this is what I actually need, since I must keep backwards compatibility. I usually end up just renaming the field foo_deprecated to indicate that it's not supposed to be written, but it would be nice to have something like deprecated_readonly or whatever so that it would be a compile error to write to it, even by accident.

[Zguy]

I felt inspired, and made an attempt at an implementation. PR here: https://github.com/google/flatbuffers/pull/8192